Cyclic olefin-derived resin fiber and cyclic olefin-derived resin non-woven fabric

ABSTRACT

Provided is a cyclic olefin-derived resin microfiber and a cyclic olefin-derived resin non-woven fabric. A polymer solution containing a volatile solvent and a cyclic olefin-derived resin is subjected to electrostatic spinning. The volatile solvent to be used preferably contains at least one solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and decalin. In addition, by using a cyclic olefin-derived resin with a glass transition point of at least 160° C., high heat-resistance can be imparted to a cyclic olefin-derived resin fiber.

TECHNICAL FIELD

The present invention relates to a cyclic olefin-derived resin fiber formed by electrostatic spinning, and a cyclic olefin-derived resin non-woven fabric.

BACKGROUND ART

As fibers configuring a non-woven fabric are made to have a smaller fiber diameter, a variety of superior performances such as separation performance, liquid holding performance, wiping performance, masking performance, insulation performance and plasticity are achieved. Thus, minimizing the diameter of the fibers configuring a non-woven fabric is desired.

As a method for producing such a non-woven fabric configured with fibers having a small fiber diameter, electrostatic spinning is exemplified. The electrostatic spinning is a process of spinning to form a microfiber and a non-woven fabric in a single step, in which a high voltage is applied between a nozzle tip charged with a polymer solution and a collector substrate, whereby an electrostatic repulsive force makes the polymer solution ultrafine and concurrently the volatile solvent contained in the polymer solution is evaporated, and then the polymer is collected. The resin which may be contained in the polymer solution is exemplified by a polypropylene resin, a polyethylene resin, and the like.

On the other hand, in recent years, techniques relating to organic materials in electronics field as well as environment and energy field have markedly developed, and thus performances required for organic materials vary extensively such as heat resistance, dimension accuracy, electric characteristics, and the like. As reduction in size and weight of parts is demand, a variety of processing configurations have been also desired. In particular, cyclic olefin-derived resins have been noticed as a material which is amorphous, and is particularly superior in transparency and heat resistance, as well as electric characteristics at high frequencies. Thus, if the aforementioned cyclic olefin-derived resin is used, performance of microfibers, and non-woven fabrics configured with microfibers can be improved.

However, practical production of a cyclic olefin-derived resin fiber having a fiber diameter in the nano size order, and a cyclic olefin-derived resin non-woven fabric by electrostatic spinning have not been reported. Furthermore, practical applications of cyclic olefin-derived resins as fibers have not been progressing.

As a cyclic olefin-derived resin fiber, for example, fibers having a fiber diameter falling within the range of from 10 μm to 100 μm formed by melt spinning was proposed in Japanese Unexamined Patent Application, Publication No. 2005-171404. However, a microfiber, and a non-woven fabric configured with microfibers have not been available.

SUMMARY

As described in the foregoing, cyclic olefin-derived resins have superior electric characteristics, and heat resistance. Thus, a variety of applications can be broadened by producing a cyclic olefin-derived resin microfiber, and a non-woven fabric configured with the microfiber. Accordingly, a cyclic olefin-derived resin microfiber, and a non-woven fabric configured with the microfiber have been desired.

The present invention was made in order to solve the foregoing problems, and an object of the invention is to provide a cyclic olefin-derived resin microfiber, and a cyclic olefin-derived resin non-woven fabric.

Means for Solving the Problems

The present inventors have thoroughly researched in order to solve the above-described problems. As a result, it was found that electrostatic spinning of a polymer solution including a volatile solvent and a cyclic olefin-derived resin enables a cyclic olefin-derived resin fiber having an average fiber of 0.01 μm to 10 μm, and an aggregate configured with the cyclic olefin-derived resin fibers to be formed. Accordingly, the present invention was accomplished. More specifically, the present invention provides the following.

A first aspect of the invention provides a cyclic olefin-derived resin fiber having an average fiber diameter of from 0.01 μm to 10 μm, in which the fiber is formed by electrostatic spinning of a polymer solution comprising a volatile solvent and a cyclic olefin-derived resin.

A second aspect of the invention provides the cyclic olefin-derived resin fiber according to the first aspect, in which the fiber has an average fiber diameter of from 0.1 μm to 0.5 μm.

A third aspect of the invention provides the cyclic olefin-derived resin fiber according to the first or second aspect, in which the volatile solvent contains at least one solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and decalin.

A fourth aspect of the invention provides the cyclic olefin-derived resin fiber according to any one of the first to third aspects, in which the cyclic olefin-derived resin has a glass transition point of 160° C. or higher.

A fifth aspect of the invention provides a cyclic olefin-derived resin non-woven fabric formed from the cyclic olefin-derived resin fiber according to any one of the first to fourth aspects.

According to the present invention, a cyclic olefin-derived resin microfiber, and an aggregate of the cyclic olefin-derived resin fibers can be formed by spinning a polymer solution containing a volatile solvent and a cyclic olefin-derived resin by electrostatic spinning.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view illustrating one example of an electrostatic spinning apparatus.

DETAILED DESCRIPTION

Hereinafter, one embodiment of the present invention is explained in detail, but the present invention is not in any way limited to the following embodiment. The present invention can be realized with appropriate modifications within the scope of the object of the invention.

The cyclic olefin-derived resin fiber, and the cyclic olefin-derived resin non-woven fabric of the present invention are characterized by being formed by spinning of a polymer solution containing a volatile solvent and a cyclic olefin-derived resin by electrostatic spinning.

The polymer solution used in the present invention contains a cyclic olefin-derived resin, and a volatile solvent. The present invention is characterized in that a cyclic olefin-derived resin is used.

Cyclic Olefin-Derived Resin

The cyclic olefin-derived resin used in the present invention contains a cyclic olefin component as a copolymer component, and is not particularly limited as long as it is a polyolefin-derived resin containing a cyclic olefin component in the main chain thereof. For example, an addition polymer of a cyclic olefin or a hydrogenated product thereof, an addition copolymer of a cyclic olefin and α-olefin, or a hydrogenated product thereof, and the like may be included.

Moreover, as a cyclic olefin-derived resin containing a cyclic olefin component as a copolymer component used in the present invention includes the aforementioned polymer being further grafted and/or copolymerized with an unsaturated compound having a polar group.

The polar group may include, for example, carboxyl groups, acid anhydride groups, epoxy groups, amide groups, ester groups, hydroxyl groups, or the like. Examples of the unsaturated compound having a polar group include (meth)acrylic acid, maleic acid, maleic anhydride, itaconic anhydride, glycidyl (meth)acrylate, (meth)acrylic acid alkyl (1 to 10 carbon atoms) esters, maleic acid alkyl (1 to 10 carbon atoms) esters, (meth)acrylamide, 2-hydroxyethyl (meth)acrylate, and the like.

In the present invention, the addition copolymer of cyclic olefin and α-olefin, or a hydrogenated product thereof can be preferably used.

In addition, a commercially available resin can be used for the cyclic olefin-derived resin (A) containing a cyclic olefin component as a copolymer component which may be used in the present invention. The commercially available cyclic olefin-based resins (A) may include, for example, TOPAS (registered trademark, manufactured by TOPAS Advanced Polymers), Apel (registered trademark, manufactured by Mitsui Chemical Co.), ZEONEX (registered trademark, manufactured by ZEON Corp.), ZEONOR (registered trademark, manufactured by ZEON Corp.), ARTON (registered trademark, manufactured by JSR Corp.), and the like.

The addition copolymer of cyclic olefin and α-olefin preferably used in the present invention is not particularly limited. Particularly preferable examples include copolymers containing [1] an α-olefin component having 2 to 20 carbon atoms and [2] a cyclic olefin component represented by the following general formula (I):

wherein, R¹ to R¹² may be the same or different from one another, and are each selected from the group consisting of a hydrogen atom, a halogen atom and a hydrocarbon group;

R⁹ and R¹⁰, and R¹¹ and R¹² may be combined to form a bivalent hydrocarbon group;

R⁹ or R¹⁹ may a form a ring with R¹¹ or R¹² with each other;

n represents 0 or a positive integer; and

when n is 2 or greater, R⁵ to R⁸ may be the same or different from one another, in each repeating unit.

[1] α-Olefin Component having 2 to 20 Carbon Atoms

The α-olefin having 2 to 20 carbon atoms preferably used in the present invention, which serves as a copolymer component of the addition polymer that is formed by copolymerization of the cyclic olefin component and other copolymer component such as ethylene, is not particularly limited. For example, olefin components similar to those disclosed in Japanese Unexamined Patent Application, Publication No. 2007-302722 may be included. In addition, these α-olefin components may be used either alone, or two or more kinds thereof may be used simultaneously. Among these, use of ethylene alone is most preferred.

[[2] Cyclic Olefin Component Represented by the General Formula (I)]

The cyclic olefin component represented by the general formula (I) preferably used in the present invention, which serves as a copolymer component in the addition polymer that is formed by copolymerization of the cyclic olefin component and other copolymer components such as ethylene, is described.

R¹ to R¹² in the general formula (I) may be the same or different from one another, and are each selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group.

Specific examples of R¹ to R⁸ may include, for example, a hydrogen atom; halogen atoms such as fluorine, chlorine and bromine; lower alkyl groups such as a methyl group, an ethyl group, a propyl group and a butyl group. These may be different from one another, partially different, or entirely the same.

Specific examples of R⁹ to R¹² may include, for example, a hydrogen atom; halogen atoms such as fluorine, chlorine and bromine; alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group and a stearyl group; cycloalkyl groups such as a cyclohexyl group; substituted or unsubstituted aromatic hydrocarbon groups such as a phenyl group, a tolyl group, an ethylphenyl group, an isopropylphenyl group, a naphthyl group and an anthryl group; a benzyl group, a phenethyl group, and aralkyl groups formed by substitution of an alkyl group with an aryl group, and the like. These may be different from one another, partially different, or entirely the same.

Specific examples of the case in which R⁹ and R¹⁰, or R¹¹ and R¹² are combined to form a bivalent hydrocarbon group include, for example, alkylidene groups such as an ethylidene group, a propylidene group and an isopropylidene group, and the like.

When R⁹ or R¹⁰ forms a ring with R¹¹ or R¹², the resultant ring may be either monocyclic or polycyclic, may be polycyclic having crosslinking, may be a ring having a double bond, or may be a ring constituted with any combination of these rings. In addition, these rings may include a substituent group such as a methyl group.

Specific examples of the cyclic olefin component represented by the general formula (I) include similar cyclic olefin components to those disclosed in Japanese Unexamined Patent Application, Publication No. 2007-302722.

These cyclic olefin components may be used alone or in combinations of two or more kinds thereof. Among them, use of bicyclo[2.2.1]hept-2-ene (common name: norbornene) alone is preferable.

It is preferred that the cyclic olefin-derived resin has a glass transition point of no less than 160° C. As the glass transition point (Tg), a value determined according to a DSC method (described in JIS K7121) under conditions of a rate of temperature increase of 10° C./min is employed. By using the cyclic olefin-derived resin having a glass transition point of no less than 160° C., sufficient heat resistance can be imparted to the cyclic olefin-derived resin fiber and the cyclic olefin-derived resin non-woven fabric.

For producing a cyclic olefin-derived resin microfiber with the electrostatic spinning, it is necessary to adjust the viscosity of the polymer solution to be suited for electrostatic spinning. Since a preferred range of the polymer concentration in the polymer solution is limited as described later, it is necessary to have a desired viscosity in the range of such a polymer concentration. Although may vary depending on the cyclic olefin-derived resin and the volatile solvent used, the content of the cyclic olefin component in the cyclic olefin-derived resin preferably falls within the range of from 60% by mass to 90% by mass since the aforementioned desired viscosity is more likely to be attained.

The method for polymerizing [1] an α-olefin component having 2 to 20 carbon atoms and [2] a cyclic olefin component represented by the general formula (I), and the method for hydrogenating the resultant polymer are not especially limited, and can be carried out according to publicly known methods. Although it may be carried out by either random copolymerization or block copolymerization, random copolymerization is preferable.

In addition, the polymerization catalyst that may be used is not particularly limited, and the polymer can be obtained by using a conventionally well-known catalyst such as a Ziegler-Natta series, metathesis series, or metallocene series catalyst according to a well known process. The addition copolymer of cyclic olefin and α-olefin or the hydrogenated product thereof that is favorably used in the present invention is preferably manufactured by use of a metallocene series catalyst.

An exemplary metathesis catalyst may be a molybdenum or tungsten series metathesis catalyst that is well-known as a catalyst for ring-opening polymerization of cycloolefin (for example, as described in Japanese Unexamined Patent Applications, First Publication Nos. S58-127728, S58-129013, etc.). In addition, the polymer obtained with the metathesis catalyst is preferably hydrogenated using a transition metal catalyst supported on an inorganic support, at a rate of no less than 90% of the double bond in the main chain, and at a rate of no less than 98% of the carbon-carbon double bond in the aromatic ring of the side chain.

[Other Copolymer Component]

The cyclic olefin-derived resin (A) may contain, in addition to the α-olefin component having 2 to 20 carbon atoms [1], and the cyclic olefin component represented by the general formula (I) [2], other copolymerizable unsaturated monomer component as needed within a range not to impair the object of the present invention.

The unsaturated monomer, which may be optionally copolymerized, is not particularly limited, and for example, hydrocarbon based monomers including two or more carbon-carbon double bonds in one molecule and the like may be exemplified. Specific examples of the hydrocarbon based monomer having two or more carbon-carbon double bonds in one molecule include those disclosed in Japanese Unexamined Patent Application, Publication No. 2007-302722.

[Other Components]

The cyclic olefin-derived resin used in the present invention may be prepared into a cyclic olefin derived resin composition by including other resin in the range not to deteriorate the effects of the invention. In addition, a composition prepared by adding an additive such as a nucleating agent, carbon black, a pigment such as an inorganic baking pigment, an antioxidant, a stabilizer, a plasticizer, a lubricant, a release agent and a fire retardant in the range not to deteriorate the effects of the invention, thereby imparting a desired characteristic, is also included in the cyclic olefin-derived resin used in the present invention.

[Physical Properties and the like of Cyclic Olefin-Derived Resin]

The weight average molecular weight of the cyclic olefin-derived resin as measured by the method described in Examples is preferably from 50,000 to 200,000. In order to provide fibers by electrostatic spinning, it is necessary to entangle the polymers in the polymer solution. When the weight average molecular weight of cyclic olefin-derived resin falls within the above range, polymers are sufficiently entangled with one another, whereby the cyclic olefin-derived resin microfiber is likely to be formed. Also in view of providing a polymer solution with a viscosity suited for spinning by electrostatic spinning, the weight average molecular weight preferably falls within the above range.

In order to adjust the viscosity of the polymer solution to fall within a desired range in the range of the polymer concentration described later, the melt viscosity of the cyclic olefin-derived resin as measured in accordance with ISO 11443 at 260° C. and a shear rate of 1,216/sec preferably falls within the range of from 50 Pa·s to 400 Pa s.

Volatile Solvent

The volatile solvent is not particularly limited as long as it dissolves the cyclic olefin-derived resin. The volatile solvent may be a mixed solvent prepared by mixing at least two kinds of solvent. The cyclic olefin-derived resin is likely to be dissolved in a solvent such as chloroform, toluene, xylene, cyclohexane, or decalin. Cyclic olefin-derived resins are also likely to be dissolved in these volatile solvents.

As described above, the cyclic olefin-derived resin is likely to be dissolved in various solvents. Consequently, the cyclic olefin-derived resin fiber of the present invention is also characterized in that it can readily be subjected to electrostatic spinning. Conventionally, predominant resins used in electrostatic spinning include polyethylene and polypropylene, and these resins have a problem of poor solubility unless a hot solvent is employed. According to the cyclic olefin-derived resin fiber of the present invention, these problems are precluded.

In particular, when microfibers are produced by electrostatic spinning, evaporation speed of the volatile solvent is an important physical property. Solutions which may be employed when the evaporation speed of the volatile solvent matters include a method in which the nozzle shape is controlled, a method in which a mixed solvent is used, method in which the atmospheric temperature and humidity are adjusted, and the like. Of these, a method in which a mixed solvent is used is particularly convenient. For carrying out the method in which a mixed solvent is used, it is preferred that the resin composition is dissolvable in various solvents. The cyclic olefin-derived resin used in the present invention is dissolved in a variety of volatile solvent as described above, and is easily dissolved also in mixed solvents prepared using these solvents. As a result, the aforementioned problem of the evaporation speed can be easily solved, and a cyclic olefin-derived resin microfiber can be readily produced.

In antistatic methods, when a polymer solution is supplied with a nozzle, stain and clogging of the nozzle needle are likely to occur if the volatile solvent consists of only a component having a low boiling point that is no greater than 100° C. at normal atmospheric pressures. Thus, this problem can be overcome by using a volatile solvent that contains not less than 20% by mass of a solvent having a boiling point of not less than 140° C. at normal pressures. As described above, also in the case in which a volatile solvent having a low boiling point is used, nozzle needle clogging and nozzle needle stain can be prevented by mixing a volatile solvent having a high boiling point, whereby continuous and stable production of the microfiber is enabled. Since the cyclic olefin-derived resin used in the present invention is dissolvable in various solvents, the range of options of the solvent is broad, and problems of clogging of needles and the like are likely to be solved.

Polymer Solution

The polymer solution is prepared by dissolving the cyclic olefin-derived resin in the volatile solvent.

Although the polymer concentration of the polymer solution used in the present invention may vary depending on the molecular weight of the polymer employed, for example, when the weight average molecular weight of the polymer used is about 90,000, the polymer concentration preferably falls within the range of from 3% by mass to 20% by mass. More preferably, the polymer concentration is from 7% by mass to 10% by mass. A polymer concentration of less than 3% by mass is not preferred since the viscosity of the solution becomes so low that formation of a fiber structure may be difficult. On the other hand, a polymer concentration exceeding 20% by mass is not preferred since the viscosity of the polymer solution becomes so high that the formed fiber has a too large fiber diameter.

The viscosity of the polymer solution preferably falls within the range of from 400 cps to 1000 cps as measured with a rotation viscometer.

Electrostatic Spinning Method

Spinning can be carried out using an electrostatic spinning apparatus 1 as shown in FIG. 1. A polymer solution is placed into a solution bath 11, and concomitant with extruding the polymer solution from a nozzle needle 12 at an arbitrary flow rate, a high voltage is applied to the nozzle needle 12 with a high voltage generator 13 to permit formation of an electric field on a copper plate 14 connected to ground with the nozzle needle 12. The polymer in the polymer solution extruded into the electric field is disrupted by Coulomb repulsion and further stretched, and the cyclic olefin-derived resin fibers are collected on the copper plate as shown in FIG. 1.

Although the magnitude of the applied voltage is not particularly limited, it is preferably from 5 kV to 100 kV. The applied voltage of less than 5 kV is not preferred since Coulomb repulsion is reduced, whereby providing fibers tends to be difficult. The applied voltage beyond 100 kV is not preferred since spark is generated between electrodes, and thus spinning may fail. More preferable applied voltage ranges from 10 kV to 30 kV.

Although the internal diameter of the nozzle needle 12 is not particularly limited, it is preferably from 0.05 mm to 2 mm, and more preferably from 0.1 mm to 1 mm taking into consideration the balance of the productivity and the resulting fiber diameter.

Also the speed of supplying the polymer solution is not particularly limited, and the speed may be predetermined by finding an appropriate value while changing various types of conditions, depending on the fiber diameter of the intended fine fibers. When the speed of supply is too great, the volatile solvent is not evaporated sufficiently, and a desired microfiber may not be formed due to influences such as the Coulomb repulsion of the droplet becoming insufficient, and the like. In addition, too low speed of supply is not preferred since the productivity of the fiber is deteriorated.

Preferable range of the speed of supplying the polymer solution is from 0.01 ml/min to 0.1 ml/min per the nozzle needle.

The distance between the tip of the nozzle needle 12 and the copper plate 14 is preferably from 5 cm to 30 cm, although it may vary depending on the solvent and the cyclic olefin-derived resin employed.

Cyclic Olefin-Derived Resin Fiber

According to the present invention, a cyclic olefin-derived resin microfiber can be formed by appropriately predetermining the cyclic olefin-derived resin, the volatile solvent, and the conditions of the electrostatic spinning. The “microfiber” means fibers having an average fiber diameter thereof being from 0.01 μm to 100 μm. According to the present invention, the average fiber diameter of from 0.1 μm to 0.5 μm can be readily attained.

In the electrostatic spinning, since fine fibers are usually obtained in the form of being laminated on the copper plate 14, these can be used as a non-woven fabric. Therefore, according to the present invention, a non-woven fabric configured with the fiber of the present invention is provided. The aforementioned non-woven fabric can be utilized as a battery separator, a medium for cell culture, and the like.

EXAMPLES

Hereinafter, the present invention is explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Materials [Cyclic Olefin-Derived Resin]

Cyclic olefin-derived resin 1: TOPAS 8007F-04 (manufactured by TOPAS Advanced Polymers, Inc.)

Cyclic olefin-derived resin 2: TOPAS 6013F-04 (manufactured by TOPAS Advanced Polymers, Inc.)

Cyclic olefin-derived resin 3: TOPAS 6015F-04 (manufactured by TOPAS Advanced Polymers, Inc.)

Cyclic olefin-derived resin 4: TOPAS 6017F-04 (manufactured by TOPAS Advanced Polymers, Inc.)

Cyclic olefin-derived resin 5: TOPAS 5013S-04 (manufactured by TOPAS Advanced Polymers, Inc.)

[Volatile Solvent]

Mixed solvent of chloroform (boiling point: 62° C.) and xylene (boiling point: 144° C.), with the mixing ratio being 80:20

[Electrostatic Spinning Apparatus]

Electrostatic spinning apparatus: nanofiber electrospinning unit (manufactured by KATO TECH CO., LTD.)

EXAMPLES

Materials presented in Table 1 were subjected to spinning using the aforementioned electrostatic spinning apparatus, by an antistatic method under conditions shown in Table 1. A non-woven fabric configured with the cyclic olefin-derived resin fiber was formed. It is to be noted that even if spinning was continued for 8 hrs or longer, clogging and staining of the nozzle needle did not occur.

[Measurement of Average Fiber Diameter]

The average fiber diameter of the cyclic olefin-derived resin fibers included in the non-woven fabrics configured with the cyclic olefin-derived resin fibers of Examples 1 to 5 was measured using a scanning electron microscope. Specifically, the diameter of arbitrary ten fibers was measured at a magnification of from 5,000 to 10,000 times, and the average value was defined as the average fiber diameter. The results of measurement are shown in Table 1.

TABLE 1 Dis- Amount tance Poly- Spin- of dis- Ap- be- Cyclic mer ning charge plied tween Fiber olefin- concen- tem- per volt- elec- diam- derived Tg tration per- nozzle age trodes eter resin (degC) (wt %) ature (ml/hr) (kV) (cm) (μm) Ex- Cyclic 78 10 room 0.8 20 15 0.5 am- olefin- tem- ple 1 derived per- resin 1 ature Ex- Cyclic 138 10 room 0.8 20 15 0.5 am- olefin- tem- ple 2 derived per- resin 2 ature Ex- Cyclic 158 10 room 0.8 20 15 0.5 am- olefin- tem- ple 3 derived per- resin 3 ature Ex- Cyclic 178 10 room 0.8 20 15 0.5 am- olefin- tem- ple 4 derived per- resin 4 ature Ex- Cyclic 133 10 room 0.8 20 15 0.4 am- olefin- tem- ple 5 derived per- resin 5 ature

As shown in Table 1, it was verified that cyclic olefin-derived resin microfibers can be formed by electrostatic spinning. 

1. A cyclic olefin-derived resin fiber having an average fiber diameter of from 0.01 μm to 10 μm, wherein the fiber is formed by electrostatic spinning of a polymer solution comprising a volatile solvent and a cyclic olefin-derived resin.
 2. The cyclic olefin-derived resin fiber according to claim 1, wherein the fiber has an average fiber diameter of from 0.1 μm to 0.5 μm.
 3. The cyclic olefin-derived resin fiber according to claim 1, wherein the volatile solvent contains at least one solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and decalin.
 4. The cyclic olefin-derived resin fiber according to claim 1, wherein the cyclic olefin-derived resin has a glass transition point of 160° C. or higher.
 5. A cyclic olefin-derived resin non-woven fabric formed from the cyclic olefin-derived resin fiber according to claim
 1. 6. The cyclic olefin-derived resin fiber according to claim 2, wherein the volatile solvent contains at least one solvent selected from the group consisting of chloroform, toluene, xylene, cyclohexane and decalin.
 7. The cyclic olefin-derived resin fiber according to claim 2, wherein the cyclic olefin-derived resin has a glass transition point of 160° C. or higher.
 8. A cyclic olefin-derived resin non-woven fabric formed from the cyclic olefin-derived resin fiber according to claim
 2. 